In a healthy person, the pleural chest cavity is generally an airtight, airless environment. During normal respiration, the contraction of the diaphragm increases the volume of the cavity, which in turn decreases the pressure therein and causes the lungs to expand. Normally, air cannot enter or escape the pleural cavity.
Patients who have fluid or air in this cavity may be treated by inserting a chest tube into the pleural cavity to drain this fluid or air. The chest tube typically comprises a plastic tube having drainage holes at its tip and in a section of its sidewall and is inserted through an incision in the wall of the patient's chest. Ordinarily, the tube is connected to a collection container for holding the drained fluids. When the cavity of a given patient has been drained and the underlying cause of the fluid buildup has been addressed, the chest tube must be removed from the patient. This is done conventionally by withdrawing the tube and suturing the incision closed. In some patients, most notably children, no suturing is done, and petroleum jelly is used to seal the opening around the chest tube during the withdrawal of the tube. A gauze dressing is then placed over the incision and secured to the skin. However, if an inspiration occurs while the tube is partially pulled or before the incision is sealed, air can enter the pleural cavity due to the negative pressure therein.
Pneumothorax, or the passage of air into the pleural cavity, is undesirable because it allows the chest cavity to lose pressurization and decreases the expansion capability of the lungs. Complications of pneumothorax can include the collapse of part or all of a lung caused by pressure from free air in the chest cavity between the two layers of the pleura, which are thin membranes that cover the lung. Further complications associated with pneumothorax include respiratory failure and lung infection. Hospitalization and treatment with special equipment following minor surgery may be necessary for patients who suffer from pneumothorax.
Pneumothorax risk while removing a chest tube from a patient may be minimized by limiting the amount of air that can enter the chest cavity during and after removal of the tube. Ordinarily, upon removal of the chest tube from the body, a doctor or technician will attempt to hold the opening into the chest closed with the hand while undertaking to suture or bandage the opening. In many cases, however, the dressing placed over the opening is not completely air impermeable, or the attendant may have difficulty holding the opening closed while suturing the opening. While the pressure leaks may be minimal, these procedures are cumbersome to undertake, and the relatively minor leaks may compromise pressurization within the chest cavity and cause the patient some distress while breathing. More seriously, dressings or sutures may become completely undone, thereby allowing the cavity to depressurize more rapidly. This would, of course, more severely affect the ability of the patient to respirate properly and complicate a pneumothorax condition.